(1) Field of the Invention
The present invention relates to methods and apparatus for gas and liquid contact and more particularly to methods and apparatus for injecting a gas into a liquid medium.
(2) Brief Description of the Prior Art
The prior art method for producing bubbles in a liquid is essentially shown in FIG. 1. In this figure there is a liquid containment surface that is a wall 10, and on one side of this wall 10 there is liquid 12 which has a velocity profile 14. The apparatus also includes a gas source 16 that is connected by gas line 18 to gas flow regulator 20 that is connected by line 22 to plenum 24. There is an aperture 26 in wall 10 through which a gas bubble 28 is formed. It will be observed that this bubble grows in size and bubbles are continuously formed as, for example, bubble 30 and bubble 32.
Basically, the gas under pressure is forced through the aperture in the wall. As the gas enters the liquid, it grows until the local shear force is large enough to rip it from the wall as shown. In the case of a strong shear flow, bubbles on the order of the pore size may be produced. Changes in the gas flow rate predominately impact the rate at which bubbles are formed and not their size. To control the size of bubbles produced from such a device, the fluid flow must be controlled at the aperture. The control of the fluid flow is either impossible or impractical to any real degree for many applications.